Individual semiconductor devices, such as for example, an integrated circuit or a semiconductor die, are typically produced by creating and assembling the devices (singulated die) into a package or multiple chip package by using well known semiconductor assembly processing techniques that can include, for example, wafer cleaning, wafer taping, dicing, die attachment, wire bonding, molding, lead frame attachment, lead trimming, lead forming and singulation. These semiconductor assembly processes create functional integrated circuit devices (ICs) in an individual package, multi-chip module (MCM), or stack chip assembly.
The fundamentals of a thermal compression with or without ultrasonic assist wire bond process consists of feeding of a thin copper or gold wire through a capillary tube. An electrode or some other mechanism is used to heat the end of the wire extruding from the capillary tube to form a free air ball of molten wire. The capillary tube is lowered towards the semiconductor device and the molten wire ball is compressed between the end of the capillary tube and a heated metal pad or other metal frame producing a mechanical connection that is intended to form a eutectic bond between the wire ball and the bond pad or frame. The capillary tube then may be raised while the wire is fed through the capillary tube leaving the wire ball attached to the die bond pad or frame. The capillary tube may be moved to second location and the thermal compression (with or without ultrasonic assist) wire bond process is repeated at the second location. This wire bonding process is repeated as required to provide electrical connection between the semiconductor device (die) bond pads and frame to provide electrical connection pathways. For example, U.S. Pat. Nos. 7,621,436 and 5,485,949 and https://en.wikipedia.org/wiki/Wirebonding, all of which are incorporated herein by reference, disclose examples of wire bonding processes and machines.
Various materials may be used to promote the melting of the bond wire and to assist in promoting the formation of the eutectic bond during the bonding process. For example, fluxes may be used to prevent oxidation during the bonding process as well as other materials. During the bonding process, some of these materials form slag and small pieces of the molten bond wire inadvertently stick to the face and side of the capillary tube.
Today the cleaning of the capillary tube is performed by removing the capillary tube from the equipment to be cleaned and/or refurbished. The cleaning and refurbishing of the capillary tube usually consists of a wet chemical process using solvents or corrosive solutions and possibly in conjunction with some mechanical scrubbing process. Thus, the typical process requires the wire bonding process to be stopped while the capillary tube is being cleaned and refurbished. Furthermore, the wet chemical process and mechanical scrubbing process can damage the capillary tube. It is desirable to be able to clean the capillary tube of the wire bonding assembly machine without removing the capillary tube and without using the harsh wet chemical process or mechanical scrubbing process.